Method of assembling and sealing a mirror assembly



Jan.2,1968 A RCWCK ETAL 3,360,847

METHOD OF ASSEMBLlNG AND SEALING A MIRROR ASSEMBLY l Original Filed Nov. 16, 1960 2 Sheets-Shee 1 fray/V59@ Jan. 2, 1968 A. R. CHICK Em 3,360,847

METHOD OF ASSEMBLING AND SEALNG A MIRROR ASSEMBLY fran/vzw United States Patent O 3,360,847 METHOD OF ASSEMBLING AND SEALING A MIRROR ASSEMBLY Albert R. Chick, New York, N.Y., and Robert K. Stortz,

Brookfield, Wis., assignors to C. M. Hall Lamp Company, Detroit, Mich., a corporation of Michigan Continuation of application Ser. No. 69,616, Nov. 16, 1960. This application July 24, 1964, Ser. No. 385,027 1 Claim. (Cl. 29-451) ABSTRACT OF THE DISCLOSURE There is herein disclosed an outside-type vehicular mirror assembly comprising a housing providing a mirror opening and a surrounding mirror seat supporting a mirror an'd mirror gasket and held in place by an inwardly turned lip. There is `a-lso disclosed an assembly method wherein the mirror and gasket are mounted on the seat and the lip is subsequently turned inwardly, and an assembly method wherein the lip is turned inwardly and then the mirror and gasket are forced over the lip onto the seat.

This invention relates tothe method of securing mirrors in cast or molded holders and is a continuation application of copending application S.N. 69,616, filed Nov. 16, 1960, now abandoned.

The majority of commercial automotive outside rear view mirrors have included' a drawn metal head which is anged over the exposed face of the mirror glass to retain the mirror in position. With the advent of molded and die cast mirror heads, other means for securing the mirror` glass` to the head have been employed. In the common practice, the rear surface, or a portion thereof, is cemented to a backing flange or plate formed in or secured within the head. It has proved difficult to establish bonds which will adequately secure the mirror to the vhead against the effects of vibration and'ambient conditions.

It is an object of this invention to improve the method of securing a mirror member in a cast or molded head or housing.

The manner of accomplishing the Iforegoing object and other objects, features, and advantages of the present invention will become apparent from the subsequent desoription, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is an elevational view of a mirror embodying certain of the features of this invention;

FIGURE 2 is a fragmentary sectional view taken along the line 2 2 in FIGURE ll; l

FIGURE 3 is a fragmentary sectional side elevational view of a mirror assembly and rolling means, illustrating one method of manufacturing the mirror;

FIGURE 4 is a fragmentary sectional view of a co'nstruction similar to that shown in FIGURE 2, during a stage of its manufacture;

FIGURE 5 is a fragmentary sectional view of the em- -bodiment of FIGURE 4, upon completion;

FIGURE 6 is a fragmentary sectional view of a modification of the construction shown in FIGURE 2 during a stage of its manufacture;

FIGURE 7 is a fragmentary sectional view of the embodiment of FIGURE 6 as completed;

FIGURE 8 is a Ifragmentary sectional view of an embodiment similar to that shown in FIGURE 7, during a stage of its manufacture; and

FIGURE 9 is a fragmentary sectional view of the embodiment of FIGURE 7, upon completion.

While various shaped housings, comprising a peripheral wall radially defining a volume and an opening at one end, could be used, a generally conically-shaped mirror head ICC or housing 10 is illustrated in FIGURE 1 by way of example and is shown mounted in a conventional manner on a base 12. The mirror housing 10 (FIGURE 2) has a radially inwardly extending annular shoulder or backing surface 14 for receiving an assembly comprising a rear surface mirror member 15 with an annular channel gasket or sealing member 16 enveloping its peripheral edge. The gasket 16 and mirror member 15, with its reflecting side 17 facing axially outward, are secured to the shoulder 14 of the housing 10 by the overlapping engagement of a folded retaining portion 19 of an annular lip 18 which is integral with the housing 10.

The mirror housing 10 is die cast from a reason-ably ductile metal which facilitates cold forming or rolling, such as Zainac, which has a composition of approximately zinc and 20% aluminum. The gasket 16 has a generally U-shaped or channel cross-section and is of a semirigid plastic such as polyethylene or the like.

In one method of manufacturing a mirror having a construction as shown in FIGURE 2, the first step is placing an assembly comprising the mirror member 15 and the channel gasket 16 upon the shoulder 14 within the mirror housing 10. Next, rolling means, exemplified by the rolling apparatus 26 in FIGURE 3, is positioned along the axis of the mirror housing 10 and in contact wtih the central portion of the mirror member 15 -by means of a spring 28 and a flat plate 30. As 'the rolling apparatus 26 is moved axially towards the mirror housing 10, the force created by the spring 28 and transmitted by the plate 30 forces the mirror member 15 to seat positively against the shoulder 14. Further axial movement of the rolling apparatus 26 brings rollers 32, which are rotatably secured to the rolling apparatus 26 by shafts 34, into contact with the annular lip 18. The rolling apparatus 26 is then simultaneously rotated and moved axially towards the mirror member 15 until a folded retaining portion 19 is formed on the axially outwardly extending annular lip 18 and is rolled inwardly into contact with the channel gasket 16. The lip 18 yields readily since it is made of a relatively ductile alloy material, ie., zinc and aluminum. Upon completion of the rolling, the planar area defined by the periphery of the folded retaining portion 19 is less than that defined by mirror member 15; thereby locking the mirror member 15 to the' housing'10. The lrollers 32 could be provided with knurled surfaces so as to produce a decorative design on the folded retaining portion 19 during the rolling operation.

The annular lip 18 has a generally decreasing thickness vfrom its juncture with the housing 10 to the extremity of the folded retaining portion 19 in order to provide incremental bending in the formation of the folded retaining portion 19 and to avoid abrupt bending of the lip 18 at the peripheral edge of the mirror member 15. The importance of this feature is that by insuring that the lip will fold at a point removed from the edge of the mirror member the possibility -of damage tothe mirror member during the rolling operation is obviated. In the method as described above, the mirror housing 10 is plated to provide a lustrous nish before the assemb-ly and rolling operation.

In another method of sealing a mirror having a construction similar to that shown in FIGURE 2, the first step is 11o-lling the annular lip 18a (FIGURE 4) to form a radially inwardly extending folded retaining portion 19a on an unplated mirror housing 10a. Subsequently, the mirror housing 10a is plated. By plating after rolling the problems of marring, crazing, etc. associated with rolling a plated surfacce are obviated. Next, an assembly comp-rising a mirror member 15a and a channel gasket 16a is positioned in peripheral contact upon the folded retaining portion 19a. As shown in FIGURE 4, it may be observed that the mirror member and gasket are supported in parallel planar relationship with the opening and the shoulder. At

this point the planar area defined by the periphery of the folded retaining portion 19a is less than that defined by the periphery of the channel gasket 16 but is greater than the planar area defined by the periphery ofthe mirror 15a. Next, an axial force is used to press-fit the assembly past the folded retaining portion 19a against the shoulder 14a vof the housing a (FIGURE 5). It may be observed by reference to FIGURES 4 and 5 that the gasket and mirror member will be moved by the axial force in a plane parallel to the opening until the gasket is fully seated in contactc with the `wall between the lip and the shoulder in restraining engagement with the mirror to hold the mirror in the housing. In order to facilitate assembly the radial dimension of the assembly comprising the mirror member a and the channel gasket 16a is less than that of wall 21a (FIGURE 6) on the mirror housing 10a; thus, upon lassembly a slight radial gap results.

In the constructions described above, the mirror member is securely retained within the mirror housing and canf riot fall out.

The gasket serves a dual function. First, it seals the internal portions of the mirror housing from the elements, salt, etc., thereby preventing corrosion. In the case where a rear surface mirror is utilized, the seal also protects the reflective coating applied to the rear surface of the mirror from attack by the elements, salt, etc. The second function of the seal is to help absorb shocks and minimize the vibration of the mirror member within the housing, thus protecting the mirror from damage.

In a method of sealing a mirror having a construction as shown in FIGURES 6 an-d 7, the first step consists of placin-g yan annular resilient ring 24h of cork or the like on a shoulder 14b of a plated die cast mirror housing 10b. Next a mirror member 15b is placed upon the resilient ring 24b. An .annular gasket 22h, having a generally rectangular cross-section vand being of la rigid plastic such -as vinyl or the like is located peripherally upon the reflecting side 17h of the mirror member 15b (FIGURE 6). Next, an annular lip 18b is rolled by means exemplified by the rolling apparatus 26 shown in FIGURE 3 to form a 4radially inwardly folded retaining portion 19b which overlaps the mirror member 15b and gasket 22b. As assembled, the planar area defined by the periphery of the folded retaining portion 19]; is less than that defined by the mirror member 15b and also less than that defined by the outer periphery of the gasket 22h.

Another method of assembling a mirror having a construction similar to that shown in FIGURE 7 has a first step of rolling a lip 18C (FIGURES 8 and 9) of an unplated mirror housign 10c to form a radially inwardly extending retaining portion 19C. A-fter the housing 10c is plated, a mirror member 15e is located upon an annular shoulder 14e of the mirror housing 10c. Note that the mirror member 15C has a planar area less than the defined by the periphery of the folded retaining portion 19C. Next, a gasket 22cvhaving a lrectangular cross-section is positioned in peripheral contact upon the folded retaining portion 19C (FIGURE 8). At this point the planar area defined by the periphery of the folded retaining portion 19C is less than that defined-by the outer periphery of the gasket 22C. Next, an axial force is applied to the annular gasket 22C and it is press-iitted past the folded retaining portion 19C into engagement with the mirror member 15e, resulting in the construction shown in FIGURE 9. In order to facilitate assembly of the constructionv yas shown in FIGURE 9 .an-d described above, a slight radial gap exists between wall 21C of minror housing 10c and the mirror member 15C and gasket 22C.

The prior discussion as to the dual function of the gasket and as to the tapering of the lip with regard t-o the construction and method of sealing ras shown in FIGURES 2, 4 and 5 is equally applicable to the construction shown in FIGURES 7 :and 9.

While a rear surface type mirror is shown in the drawings and is discussed with regard to the vario-us constructions, it should be understood that the methods of sealing the mirror as shown above are equally applicable to a mirror having the reliezctive coating on its front side.

While it will be apparent that the preferred embodiments of the invention disclosed are Well calculated to ful- 'll the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and lchange without departing from the proper scope or fair meaning of the subjoined claims.

What is claim-ed is:

1. A method of sealing a mirror assembly comprising a cast metallic unplated mirror housing `having :a peripheral wall radially defining a volume and an opening at one end, the wall having an internally disposed peripheral shoulder located axially inwardly from the one end `and extending radially inwardly, an axially outwardly extending lip integral with the wa-ll being peripherally internally disposed between the one end and the shoulder, said method comprising the steps of placing a sealing member having a generally U-shaped `cross-section in enveloping relationship about the peripheral edge of a mirror member out side of ysaid mirror housing, rolling the axially outwardly ext-ending lip to form a radially inwardly extending folded portion. defining a planar area larger than that defined by the mirror member and smaller than that defined by the sealing member, plating the mirror housing, and the. positioning the mirro-r member and the sealing member upon the folded portion, land press-fitting the sealing member and simultaneouslyvmoving the mirror member past the folded portion to bring the sealing member into contact with the shoulder of the wall and the wall between the shoulder and the lip to hold the mirror member within the housing.

References Cited UNITED STATES PATENTS 1,811,823 7/1931 Horton 88-96 2,056,024 v9/ 1936 Stuart.

2,331,449 10/ 1943 Wittenberg 29-511 X 2,426,714 9/1947 Sonnenberg et al. 29--511 X 2,579,148 12/ 1951 Jones 88--96 CHARLIE T. MOON, Primary Examiner. 

